1. Field of the Invention
The present invention relates to the alignment of a fixed scroll and an orbiting scroll for a scroll-type fluid displacement apparatus.
2. Description of Related Art
Scroll-type fluid displacement apparatus are known in the art. The structure of a known scroll-type fluid displacement apparatus includes a housing and two scroll members an orbiting scroll and a fixed scroll, each having an end plate and a spiroidal or involute spiral wrap element extending from one side of each end plate. The housing comprises a front housing and a rear housing. The scroll members are maintained at an angular and radial offset, so that both spiral elements interfit to form a plurality of line contacts between their spiral curved surfaces to thereby seal off and define at least one pair of fluid pockets. The relative orbital motion of the two scroll members shifts the line contacts along the spiral curved surfaces and, as a result, changes the volume of the fluid pockets. The volume of the fluid pockets increases or decreases depending on the direction of orbital motion. Thus, this scroll-type apparatus is able to compress, expand, or pump fluids.
In the known scroll-type fluid displacement apparatus, two pin holes are formed in the fixed scroll or in the rear housing and the front housing, respectively, and two single diameter pins are inserted into each pin hole on the fixed scroll or the rear housing, and pin hole in the front housing. These pin holes are used to align the fixed scroll and the orbiting scroll, relative to each other.
In the known scroll-type fluid displacement apparatus, however, the alignment of the fixed scroll or the rear housing and front housing is unconditionally fixed, and the alignment of the fixed scroll and the orbiting scroll is unconditionally fixed. Therefore, the alignment of the fixed scroll and the orbiting scroll may not be finely adjusted to cope with the difference in part sizes within size tolerances. As a result, the efficiency of the compression of fluid may decrease, or the power of compression consumption may increase.
An object of the present invention is to provide a scroll-type fluid displacement apparatus which may permit fine adjustment to the alignment of a fixed scroll and an orbiting scroll.
In an embodiment, a scroll-type fluid displacement apparatus comprises a front housing, a fixed scroll, an orbiting scroll, and a driving mechanism. The fixed scroll has a first end plate and a spiral element formed on and extending from the first side of the first end plate. The fixed scroll is mounted on the front housing. The orbiting scroll has a second end plate and a spiral element formed on and extending from the first side of the second end plate. Each of the spiral elements interfits at an angular and a radial offset with the other to form a plurality of line contacts defining at least one pair of sealed-off fluid pockets. A driving mechanism includes a drive shaft rotatably supported by the front housing to effect the orbital motion of the orbiting scroll by rotation of the drive shaft and to thereby change the volume of the fluid pockets. Two pin holes are used for the alignment of the fixed scroll and the orbiting scroll. These pin holes are formed in an end surface of the spiral element of the fixed scroll and in an end surface of the front housing. The pin hole formed in the end surface of the spiral element of the fixed scroll and the pin hole formed in (or through) the end surface of the front housing have different diameters.
In another embodiment, a scroll-type fluid displacement apparatus comprises a rear housing and a front housing, a fixed scroll, an orbiting scroll, and a drive mechanism. The front housing closes the opening of the rear housing. The fixed scroll has a first end plate and a spiral element formed on and extending from the first side of the first end plate, and the fixed scroll is attached to the rear housing. The orbiting scroll has a second end plate and a spiral element formed on and extending from the first side of the second end plate. Each of the spiral elements interfits at an angular and a radial offset with the other to form a plurality of line contacts defining at least one pair of sealed-off fluid pockets. The driving mechanism includes a drive shaft, which is rotatably supported by the front housing. The rotation of drive shaft generates the orbital motion of the orbiting scroll, thereby changing the volume of the fluid pockets. Two pin holes are used for the alignment of the fixed scroll and the orbiting scroll. These pin holes are formed in an end surface of the rear housing and in an end surface of the front housing. The pin hole formed in the end surface of the rear housing and the pin hole formed in (or through) the end surface of the front housing have different diameters.
The structure of the scroll-type fluid displacement apparatus described in this invention permits the fine adjustment of the alignment of the fixed scroll and the orbiting scroll.
Other objects, features, and advantages will be apparent to persons of ordinary skill in the art from the following detailed description of the invention and the accompanying drawings.